Biological Explanations for Schizophrenia Flashcards
What are the 2 genetic explanations for schizophrenia and explain them
1) Schizophrenia runs in the family,- as seen via systematic investigations on the link between genetic similarity and shared risk of schizophrenia, seen via Gotsman et al’s large-scale family study.
2) Candidate genes- a number of genes are related with causing small increased risk in developing schizophrenia. So, schizophrenia is polygenic and atieologically heterogenous. Seen via Ripke et al’s data combining genome-wide studies. 37000 patients Genetic makeup compared to 113,000 controls and found 108 seperate genetic variations associated incl. those that coded for neurotransmitters like dopamine.
Explain the dopamine hypotheses?
Neurotransmitters work differently in schizophrenic patients, including dopamine, which is said to be responsible for functioning of several brain systems.
Hyperdopaminergia in the subcortex (origional version of the dopamine hypotheses) - excess of DA in central parts of brain ie) access of DA in Brocas area (to do w. speech production) is thought to explain speech poverty and auditory hallucinations.
Hypodopaminergia in the cortex- abnormal DA systems in the cortex ie) Goldman-Rakic found low levels of DA in the prefrontalcortex (to do . thinking and decision making) led to negative symptoms.
Explain the neural correlates of schizophrenia
Refers to the measurements of the structures or functions in the brain that correlate with an experience. Negative and positive symptoms of schiz. have neural correlates.
Neural correlates of negative symptoms- activity in the ventral Striatum is a neural correlate of negative symptoms in schiz. This is because avolition is involved w/ lack of motivation which is associated with the anticipation of rewards which is associated with the ventral striatum and as Juckel et al found, their were low acitvity levels (abnormality) in the ventral stratium of schiz. patients compared to control group.
Neural correlates of positive symptoms:
Allen et al scanned brains of patients w/ auditory hallucinations in comparison to control gorup when identifying if pre-recorded speech belonged to them or not. Found lower activity in superior temporal gyrus and anterior circulate gyrus.
